Familiarity with PET Additives for Producing Quality Bottles

Definition of PET Additives

The widespread use of polymer additives in this industry, particularly pigments, and their influence on the quality of packaging and bottles necessitates a brief overview of the types of additives employed. The combination of additives and PET granules during the preform shaping process must ensure maximum uniformity and stability to create a homogeneous mixture with the polymer. This will preserve the visual characteristics and even distribution of the additives’ properties, while also ensuring the product’s quality stability throughout the process.

How to Choose the Right PET Additive?

Consider the following points when selecting an appropriate additive:

1 If the polymer additive will be used in food packaging, confirm that it has the necessary health certifications for food contact.

2 Perform tests to validate the accuracy of the technical data provided by the supplier and the effectiveness of the additive.

3 The PET additive should offer maximum performance relative to cost, alongside the required stability and quality consistency.

4 For better integration with the polymer, it is advisable to use additives that are compatible with the desired polymer. For instance, use PET-based pigments in the production of colored preforms.

What are the Types of Polymer Additives?

Plastic additives are classified based on their application or other characteristics. Some additives serve to protect packaging plastics or their contents from environmental degradation due to light, heat, oxygen, and other aggressive factors. These include stabilizers and optical and thermal absorbers, as well as antioxidants. Another category of additives is incorporated into the polymer to enhance and control processing (such as processing aids and various lubricants).

The following additives may be utilized during polymer production or in the injection and shaping process of the PET Preform to achieve specific characteristics or applications.

Pigments

These compounds are employed to add color to the polymer. Typically, to achieve better blending and distribution within the polymer, pigments are introduced into the desired polymer base by masterbatch manufacturers in controlled percentages. In addition to their aesthetic benefits, pigments can block specific wavelengths of light from penetrating the product, depending on the coverage, color spectrum, and thickness of the film (bottle), providing optical protection for the product.

UV Blockers

New findings indicate that UV light has a greater impact on flavor, color, and nutrients than color alone. It has been noted that vitamins are affected first, followed by color when exposed to light. Generally, vitamins and nutrients are sensitive to temperature, light, and oxygen. Even slight changes in the molecular structure of food can render it biologically ineffective. Vitamins A, B2 (riboflavin), B6, B12, and folic acid are particularly susceptible to ultraviolet light.

Ultraviolet light can degrade both natural and artificial colors in foods and beverages, such as those found in fruits, fruit juices, shampoos, and dishwashing detergents. Natural colors, including red, yellow, and orange carotenoid pigments in citrus, carrots, and tomatoes, as well as blue and red anthocyanins in various berries, cherries, and grapes, are unstable under UV light. Carotenoids like lutein and beta-carotene tend to lose color when exposed to UV light. Colors added to enhance the appearance of beverages like soft drinks and fruit juices can fade due to both visible and ultraviolet light, and the presence of vitamin C as an antioxidant or small amounts of metals can expedite this process.

UV light accelerates the oxidation of fatty acids, resulting in unpleasant flavors and odors, even in low concentrations, such as in low-fat milk.

Gas Barrier Additives

These additives prevent oxygen from entering the bottle or carbon dioxide from escaping during the product’s shelf life, preserving freshness and extending shelf life. They are applicable in the packaging of fruit juices, carbonated beverages, malt beverages, and oxygen-sensitive drinks.

Aldehyde Scavenger

The migration of aldehyde from PET containers can negatively impact products like mineral water. This additive effectively reduces and controls aldehyde levels.

Other Additives

Nucleating agents and nano compounds can enhance the performance of beverage bottles or food that is hot-filled or requires pasteurization by increasing thermal resistance.

The packaging industry is rapidly advancing with modern technologies. Innovations such as nanoparticles, nanocomposites, smart sensors, and others have enhanced the desirable capabilities of packaging. Examples of these improvements include extending the shelf life of food products and developing properties such as environmental compatibility through controlled or accelerated degradation.